An ordinary domain user can join 10 members to the domain

In Windows 2000, an ordinary autheniticated domain user can add up to 10 member computers to the domain.

Once they have added 10 members, they can no longer add any more.

If you want them to be able to manage computer accounts, you must grant them the Create Computer Objects and Delete Computer Objects right on the Advanced tab of the Active Directory Users and Computers snap-in, or you can use the adsiedit.msc or Ldp.exe tool from the Windows 2000 Support Tools to override the limit.

http://www.windowsitpro.com/article/jsifaq/jsi-tip-2216-an-ordinary-domain-user-can-join-10-members-to-the-domain.aspx